Device and method for separating and removing chlorine in titanium dioxide chloride production

Abstract

The invention discloses a device and a method for separating and removing chlorine in chlorination process titanium dioxide production. The device comprises external equipment, a vertically arranged first barrel, a second barrel arranged in the first barrel, and a feeding pipeline tangentially connected to the upper part of the first barrel, the first cylinder body and the second cylinder body are both made of conductive materials, and the external equipment is electrically connected with the first cylinder body and the second cylinder body, so that a voltage difference is formed between the first cylinder body and the second cylinder body; and a plurality of vent holes penetrating through the inside and the outside of the second cylinder are formed in the second cylinder. According to the device, the vent holes are formed and matched with the tangentially-designed feeding pipeline, so that a titanium dioxide primary product can enter the position between the first barrel and the second barrel at high pressure and speed, gas and solid are separated under the action of centrifugal force and gravity, meanwhile, the separation efficiency can be greatly improved in the modes of vibration increasing, electrode adding and inert gas purging, and the separation efficiency is greatly improved. The content of chlorine adsorbed on the surface of titanium dioxide is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of titanium dioxide production by chloride process, and in particular to a device and method for separating and removing chlorine in the production of titanium dioxide by chloride process. Background Art

[0002] The production principle of titanium dioxide by chloride process is mainly that titanium tetrachloride and oxygen directly oxidize at high temperature to obtain titanium dioxide primary product and chlorine. Although most of the chlorine is removed by bag filter in the current production process, chlorine is still adsorbed on the surface of titanium dioxide primary product, causing a series of quality problems of the primary product, such as chloride ions entering the subsequent production process, resulting in pH reduction, high viscosity and other problems. Therefore, removing the chlorine element in the form of chlorine gas at the beginning of production is beneficial to improving product quality and reducing subsequent production costs. The separated chlorine gas is either collected, enriched and reused, or absorbed by alkali solution to reduce its harm to the environment and human body. The description of cyclone separator in the prior art can separate solids and gases, but no similar device is used to separate the residual chlorine gas in the chloride process titanium dioxide. The difficulty lies in the small particle size of chloride process titanium dioxide (180±20 nm) and the toxicity and corrosiveness of chlorine gas. The cyclone (cyclone separator) of the prior art can separate solids and gases, but it can usually only separate solids with a particle size greater than 0.2 mm, which cannot meet the separation requirements of primary titanium dioxide chloride.

[0003] Therefore, seeking a device or method that can effectively separate chlorine from primary titanium dioxide products is a technical problem that needs to be solved urgently by those skilled in the art.

[0004] Based on this, the existing technology still needs to be improved. Summary of the invention

[0005] In order to solve the above technical problems, the embodiments of the present invention provide a device and method for separating and removing chlorine in the production of titanium dioxide chloride, so as to solve the technical problems existing in the separation of chlorine in the primary titanium dioxide product in the prior art.

[0006] To solve the above technical problems, on the one hand, some embodiments of the present invention disclose a device for separating and removing chlorine in the production of titanium dioxide by the chloride process, comprising an external device, a first cylinder arranged vertically, a second cylinder arranged in the first cylinder, and a feed pipeline tangentially connected to the upper part of the first cylinder; Furthermore, the first cylinder and the second cylinder are both made of conductive materials, and the external device is electrically connected to the first cylinder and the second cylinder respectively, so that a voltage difference is formed between the first cylinder and the second cylinder; The second cylinder is provided with a plurality of vent holes penetrating the inside and outside of the second cylinder.

[0007] In some embodiments, the first cylinder includes a feeding portion and a blanking portion; The blanking portion extends downward from the lower end of the feeding portion, and the inner diameter gradually decreases; the feeding pipe is connected to the feeding portion; The second cylinder is arranged concentrically with the first cylinder, and the outer diameters of the second cylinders are the same along the height direction.

[0008] In some embodiments, a vibration pump is further included, wherein the vibration end of the vibration pump is arranged on the outer wall of the first cylinder.

[0009] In some embodiments, an inert gas storage tank and a recovered gas storage tank are further included, and the lower end of the second cylinder is connected to the inert gas storage tank via a non-conductive lower connecting cylinder; The upper end of the second cylinder is connected to the recovered gas storage tank via a non-conductive upper connecting cylinder.

[0010] In some embodiments, the external device includes a first electrode and a second electrode, and the first electrode and the second electrode are connected to the first cylinder and the second cylinder respectively.

[0011] In some embodiments, the first electrode and the second electrode apply positive and negative DC voltages to the first cylinder and the second cylinder respectively.

[0012] On the other hand, some embodiments of the present invention further disclose a method for separating and removing chlorine in the production of titanium dioxide chloride, which is implemented by using the aforementioned device for separating and removing chlorine in the production of titanium dioxide chloride; comprising: The mixed material discharged from the material outlet of the oxidation reactor enters the first cylinder tangentially at a predetermined pressure, and swirls downward in the gap between the first cylinder and the second cylinder. The chlorine in the mixed material enters the interior of the second cylinder through the vent hole and is discharged from the upper end of the first cylinder; the solid material is discharged from the lower end of the gap between the first cylinder and the second cylinder under the action of gravity and centrifugal force.

[0013] In some embodiments, an inert gas is injected into the second cylinder through an inert gas storage tank connected to the lower end of the second cylinder to assist in the separation of chlorine; and / or, a vibration pump is provided on the outer wall of the first cylinder to allow the material attached to the first cylinder to fall smoothly; And / or, positive and negative DC voltages are applied to the first cylinder and the second cylinder by an external device to selectively screen and separate the charged ions through the electrostatic interaction between the first cylinder and the second cylinder.

[0014] In some embodiments, titanium dioxide attached to the first cylinder and the second cylinder is cleaned by switching the electrodes of the first cylinder and the second cylinder.

[0015] In some embodiments, the predetermined pressure is 250-350 KPa.

[0016] By adopting the above technical solution, the present invention has at least the following beneficial effects: The present invention provides a device and method for separating and removing chlorine in the production of chlorinated titanium dioxide. By setting a vent hole and coordinating a tangentially designed feed pipe, the primary titanium dioxide product can enter between the first cylinder and the second cylinder at a relatively high pressure and speed, and separate gas and solid under the action of centrifugal force and gravity. At the same time, by increasing vibration, adding electrodes, and inert gas purging, the separation efficiency can be greatly improved, and the chlorine content on the surface of titanium dioxide can be reduced. The present invention removes the chlorine element when it is still in the form of chlorine gas at the initial stage of production, which is beneficial to improving product quality and reducing subsequent production costs. The separated chlorine gas is either collected, enriched, and reused, or absorbed by alkali solution to reduce its harm to the environment and human body. In addition, the particle size distribution of the titanium dioxide product separated by the device is more concentrated, and the product quality is further improved. It can be promoted and applied in the chlorinated titanium dioxide industry, and has broad prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 The present invention is a schematic diagram of the structure of a device for separating and removing chlorine in the production of titanium dioxide chloride disclosed in some embodiments of the present invention.

[0019] Description of reference numerals: 1. First cylinder; 11. Feeding part; 12. Blanking part; 2. Second cylinder; 21. Upper connecting cylinder; 22. Lower connecting cylinder; 3. Feeding pipeline; 4. Vibrating pump; 5. External equipment; 51. First electrode; 52. Second electrode; 6. Vent hole. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0021] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0022] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0024] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0025] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0026] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0027] like Figure 1 As shown, some embodiments of the present invention disclose a device for separating and removing chlorine in the production of titanium dioxide by the chloride process, comprising an external device 5, a first cylinder 1 arranged vertically, a second cylinder 2 arranged in the first cylinder 1, and a feed pipe 3 tangentially connected to the upper part of the first cylinder 1; and the first cylinder 1 and the second cylinder 2 are both made of conductive materials, and the external device 5 is electrically connected to the first cylinder 1 and the second cylinder 2 respectively, so that a voltage difference is formed between the first cylinder 1 and the second cylinder 2; the second cylinder 2 is provided with a plurality of vents 6 that pass through the inside and outside of the second cylinder 2. Generally, the material tangentially entering the first cylinder 1 should have sufficient speed or pressure. During the production process, this device is directly connected to the upstream oxidation device. The material flow rate coming out of the oxidation device is generally 30-35 m / s, and the pressure is about 350 KPa. By setting a reasonable pipeline length, pipe diameter, etc., the pressure when it enters the first cylinder 1 can be about 300 KPa.

[0028] In this embodiment, by providing a vent hole 6 and cooperating with a tangentially designed feed pipe 3, the primary titanium dioxide product can enter between the first cylinder 1 and the second cylinder 2 at a relatively high pressure and speed, and separate gas and solid under the action of centrifugal force and gravity. At the same time, the separation efficiency can be greatly improved and the chlorine content on the surface of titanium dioxide can be reduced by increasing vibration, adding electrodes, and purging with inert gas. Removing the chlorine element when it is still in the form of chlorine gas in the early stage of production is beneficial to improving product quality and reducing subsequent production costs. The separated chlorine gas can be collected, enriched, and reused, or absorbed by alkali solution to reduce its harm to the environment and human body.

[0029] Some embodiments of the present invention disclose a device for separating and removing chlorine in the production of chlorinated titanium dioxide. On the basis of the above embodiments, in order to achieve smooth feeding and maintain the flow rate and pressure after feeding to obtain sufficient centrifugal force, the first cylinder 1 includes a feeding part 11 and a blanking part 12; the blanking part 12 extends downward from the lower end of the feeding part 11, and the inner diameter gradually decreases, and the feeding part 11 is arranged with equal diameters from top to bottom, so that the speed and pressure of the material in the feeding part 11 change little; the feeding pipeline 3 is connected to the feeding part 11; the second cylinder 2 is arranged concentrically with the first cylinder 1, and, along the height direction, the outer diameter of the second cylinder 2 is the same, and as the inner diameter of the lower part of the first cylinder 1 gradually decreases, the centrifugal force and state similar to that of a cyclone are obtained during the descent of the material, and at the same time, the vent hole 6 arranged on the cylinder wall of the second cylinder 2 can not only effectively separate chlorine, but also make the particle size distribution of the titanium dioxide product obtained after separation more concentrated, and the product quality is further improved.

[0030] A device for separating and removing chlorine in the production of chlorinated titanium dioxide disclosed in some embodiments of the present invention, on the basis of the above embodiments, in order to avoid the material adhering to the inner wall of the first cylinder 1 and causing poor material discharge, a vibration pump 4 can be arranged outside the first cylinder 1, and the vibration end of the vibration pump 4 is arranged on the outer wall of the first cylinder 1, generally arranged at the lower part of the first cylinder 1, and the vibration frequency is generally set to 20-500 Hz, so as to obtain a better oscillation effect. In this embodiment, in order to further improve the removal efficiency of chlorine, an inert gas storage tank and a recovery gas storage tank can also be arranged, specifically, the lower end of the second cylinder 2 is connected to the inert gas storage tank through a non-conductive lower connecting cylinder 22; the upper end of the second cylinder 2 is connected to the recovery gas storage tank through a non-conductive upper connecting cylinder 21. Inert gas is blown into the lower end of the second cylinder 2 through the inert gas storage tank, so that a slight negative pressure state is formed at the vent 6, so that chlorine enters the second cylinder 2 more quickly and more from the gap between the first cylinder 1 and the second cylinder 2, and then enters the recovery gas storage tank as the inert gas moves upward. The recovered chlorine and inert gases can be enriched and reused, or absorbed by alkaline solution to reduce their harm to the environment and human body.

[0031] A device for separating and removing chlorine in the production of chlorinated titanium dioxide disclosed in some embodiments of the present invention, based on the above embodiments, in order to achieve a voltage difference between the conductive parts of the first cylinder 1 and the second cylinder 2, so that an electrostatic force is formed between the two. The external device 5 includes a first electrode 51 and a second electrode 52, and the first electrode 51 and the second electrode 52 are respectively connected to the first cylinder 1 and the second cylinder 2. The first electrode 51 and the second electrode 52 apply positive and negative DC voltages to the first cylinder 1 and the second cylinder 2, respectively, and selectively screen and separate charged ions through electrostatic interaction. Its maximum voltage is generally not more than the human safety voltage (0-36 V), and the voltage can be adjusted according to the operation of the equipment. If necessary, the electrodes can be turned to facilitate the cleaning of titanium dioxide adsorbed on the first cylinder 1 and the second cylinder 2. In addition, pressure, temperature and flow sensors can be installed at each inlet and outlet of the device to facilitate the understanding and adjustment of the operation of the device.

[0032] Some embodiments of the present invention also disclose a method for separating and removing chlorine in the production of titanium dioxide chloride, which is implemented by using the device for separating and removing chlorine in the production of titanium dioxide chloride of the aforementioned embodiment; comprising: the mixed material discharged from the material outlet of the oxidation reactor enters the first cylinder 1 tangentially at a predetermined pressure, and swirls downward in the gap between the first cylinder 1 and the second cylinder 2, the chlorine in the mixed material enters the interior of the second cylinder 2 through the vent 6 and is discharged from the upper end of the first cylinder 1; the solid material is discharged from the lower end of the gap between the first cylinder 1 and the second cylinder 2 under the action of gravity and centrifugal force. Generally, the separation of chlorine can also be assisted by injecting inert gas into the second cylinder 2 through an inert gas storage tank connected to the lower end of the second cylinder 2; or by arranging a vibration pump 4 on the outer wall of the first cylinder 1 to make the material attached to the first cylinder 1 fall smoothly; or by applying positive and negative DC voltages to the first cylinder 1 and the second cylinder 2 through an external device 5, the charged ions are selectively screened and separated through the electrostatic interaction between the first cylinder 1 and the second cylinder 2. This embodiment is described in the manner of or. It should be clear that the above structures do not have to be used one by one when used. They can be used alone in a certain embodiment as needed, or can be used together.

[0033] Some embodiments of the present invention also disclose a method for separating and removing chlorine in the production of chlorinated titanium dioxide. On the basis of the above embodiments, the titanium dioxide attached to the first cylinder 1 and the second cylinder 2 can be cleaned by reversing the electrodes of the first cylinder 1 and the second cylinder 2. The electrodes on the first cylinder 1 and the second cylinder 2 are instantly reversed, and the titanium dioxide adsorbed thereon is instantly subjected to completely opposite forces, and can be easily detached from the cylinder wall. When in use, a titanium dioxide chlorine mixed system with a certain flow rate enters the first cylinder 1 of the device through the feed pipe 3, and the solid and the gas are separated due to the centrifugal force and gravity. The gas flows out through the upper end of the second cylinder 2, and the solid flows out through the lower end of the gap between the first cylinder 1 and the second cylinder 2. Inert gas can be selectively introduced into the lower end of the second cylinder 2 to assist in the separation of chlorine. The external device 5 applies positive and negative DC voltages to the first cylinder 1 and the second cylinder 2, respectively, and selectively screens and separates the charged ions through electrostatic interaction. The electrodes can be reversed when necessary to facilitate the cleaning of the titanium dioxide adsorbed on the cyclone and the hollow conduit. The vibration pump 4 acts on the outside of the first cylinder 1 to promote the falling off of the titanium dioxide attached to the inner wall of the cyclone.

[0034] In summary, the device and method for separating and removing chlorine in the production of titanium dioxide chloride disclosed in the embodiment of the present invention can directly increase the slurry concentration in the post-treatment, thereby releasing production capacity and generating economic benefits. It can reduce the use of hydrogen peroxide and alkali solution in the current dechlorination process, directly reducing the production input cost. It can reduce the salt concentration of the pulping process in the subsequent production process, further improve product quality, and enhance product competitiveness. It can reduce the salt concentration in wastewater, reduce the amount of wastewater treatment, and indirectly reduce production costs. It can reduce the harm to the environment in the production process of titanium dioxide chloride, making the production technology of titanium dioxide chloride more green and environmentally friendly, and has broad prospects for promotion and application.

[0035] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0036] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A device for separating and removing chlorine in the production of titanium dioxide by the chloride process, characterized in that: It includes an external device, a first cylinder arranged vertically, a second cylinder arranged in the first cylinder, and a feed pipe tangentially connected to the upper part of the first cylinder; Furthermore, the first cylinder and the second cylinder are both made of conductive materials, and the external device is electrically connected to the first cylinder and the second cylinder respectively, so that a voltage difference is formed between the first cylinder and the second cylinder; The second cylinder is provided with a plurality of vent holes penetrating the inside and outside of the second cylinder.

2. The device for separating and removing chlorine in the production of titanium dioxide chloride according to claim 1, characterized in that: The first cylinder includes a feeding portion and a blanking portion; The blanking portion extends downward from the lower end of the feeding portion, and the inner diameter gradually decreases; the feeding pipe is connected to the feeding portion; The second cylinder is arranged concentrically with the first cylinder, and the outer diameters of the second cylinders are the same along the height direction.

3. The device for separating and removing chlorine in the production of titanium dioxide chloride according to claim 1, characterized in that: It also includes a vibration pump, wherein the vibration end of the vibration pump is arranged on the outer wall of the first cylinder.

4. The device for separating and removing chlorine in the production of titanium dioxide chloride according to claim 1, characterized in that: It also includes an inert gas storage tank and a recovered gas storage tank, and the lower end of the second cylinder is connected to the inert gas storage tank through a non-conductive lower connecting cylinder; The upper end of the second cylinder is connected to the recovered gas storage tank via a non-conductive upper connecting cylinder.

5. The device for separating and removing chlorine in the production of titanium dioxide chloride according to claim 1, characterized in that: The external device includes a first electrode and a second electrode, and the first electrode and the second electrode are connected to the first cylinder and the second cylinder respectively.

6. The device for separating and removing chlorine in the production of titanium dioxide chloride according to claim 5, characterized in that: The first electrode and the second electrode apply positive and negative DC voltages to the first cylinder and the second cylinder respectively.

7. A method for separating and removing chlorine in the production of titanium dioxide chloride, characterized in that: The method is implemented by using the device for separating and removing chlorine in the production of titanium dioxide chloride according to any one of claims 1 to 6; comprising: The mixed material discharged from the material outlet of the oxidation reactor enters the first cylinder tangentially at a predetermined pressure, and swirls downward in the gap between the first cylinder and the second cylinder. The chlorine in the mixed material enters the interior of the second cylinder through the vent hole and is discharged from the upper end of the first cylinder; the solid material is discharged from the lower end of the gap between the first cylinder and the second cylinder under the action of gravity and centrifugal force.

8. The method for separating and removing chlorine in the production of titanium dioxide chloride according to claim 7, characterized in that: Injecting inert gas into the second cylinder through an inert gas storage tank connected to the lower end of the second cylinder to assist in the separation of chlorine; and / or, a vibration pump is provided on the outer wall of the first cylinder to allow the material attached to the first cylinder to fall smoothly; And / or, positive and negative DC voltages are applied to the first cylinder and the second cylinder by an external device to selectively screen and separate the charged ions through the electrostatic interaction between the first cylinder and the second cylinder.

9. The method for separating and removing chlorine in the production of titanium dioxide chloride according to claim 7, characterized in that: The titanium dioxide attached to the first cylinder and the second cylinder is cleaned by switching the electrodes of the first cylinder and the second cylinder.

10. The method for separating and removing chlorine in the production of titanium dioxide chloride according to claim 7, characterized in that: The predetermined pressure is 250-350 KPa.

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